i would go with the cool tube, something about water and high powered equipment scares me. lol
I believe water is circulated around the bulb (and a protective glass shield?) much like a hydro system. the water absorbs the heat like a radiator and displaces it. Good in theory but......scary
I don't think I've seen anyone on this site with water cooled lights yet. Sounds like an interesting idea. To late for me. No way I'm buying all new hoods now.